Senescence-associated ß-galactosidase in subcutaneous adipose tissue associates with altered glycaemic status and truncal fat in severe obesity.

AIM/HYPOTHESIS: Altered adipose tissue secretory profile contributes to insulin resistance and type 2 diabetes in obesity. Preclinical studies have identified senescent cells as a cellular source of proinflammatory factors in adipose tissue of obese mice. In humans, potential links with obesity comorbidities are poorly defined. Here, we investigated adipose tissue senescent status and relationships with metabolic complications in human obesity. METHODS: The study includes a prospective cohort of 227 individuals with severe obesity. A photometric method was used to quantify senescence-associated ß-galactosidase (SA-ß-gal) activity in paired subcutaneous and omental adipose tissue biopsies obtained during gastric surgery. Gene and secretory profiling was performed in adipose tissue biopsies and in human primary pre-adipocytes in the presence or absence of senolytic drugs targeting senescent cells. Participants were phenotyped for anthropometric and bioclinical variables, metabolic complications and gastric surgery-induced improvement to address relationships with adipose tissue SA-ß-gal. RESULTS: SA-ß-gal activity was sevenfold higher in subcutaneous than in omental adipose tissue and not associated with BMI or chronological age. Several factors, including insulin-like growth factor binding protein 3 (IGFBP3), plasminogen activator inhibitor 1 (PAI1), C-C motif chemokine ligand 2 (CCL2) and IL-6, were upregulated in subcutaneous adipose tissue in relation with SA-ß-gal (p for linear trend across tertiles <0.05) and in pre-adipocytes cultured with inflammatory macrophage conditioned media. Senolytic treatment reduced SA-ß-gal staining and normalised these alterations. In the whole population, subcutaneous adipose tissue SA-ß-gal activity was positively associated with serum leptin, markers of insulin resistance and increased trunk fat mass. Metabolic complications, including type 2 diabetes and dyslipidaemia, were more prevalent in patients with high levels of SA-ß-gal, but improved with bariatric surgery whatever the initial adipose tissue senescent status. CONCLUSIONS/INTERPRETATION: This study highlights a phenotype of senescence in adipose tissue of severely obese individuals, which characterises prominently subcutaneous fat depots. Subcutaneous adipose tissue senescence is significantly linked to altered glucose metabolism and body fat distribution. Elimination of senescent cells through senolytic treatment could alleviate metabolic complications in severely obese people. Graphical abstract.

Branched-chain amino acids: Abundance of their transporters and metabolizing enzymes in adipose tissue, skeletal muscle, and liver of dairy cows at high or normal body condition.

Branched-chain amino acids (BCAA) are major components of milk protein and important precursors for nonessential AA. Thus, the BCAA transport and break-down play a key role in the metabolic adaptation to the high nutrient demands in lactation. However, in monogastrics, increased BCAA levels have been linked with obesity and certain metabolic disorders such as impaired insulin sensitivity. Our objective was to study the effect of over-conditioning at calving on plasma BCAA levels as well as the tissue abundance of the most relevant BCAA transporters and degrading enzymes in dairy cows during late pregnancy and early lactation. Thirty-eight Holstein cows were allocated 15 wk antepartum to either a normal- (NBCS) or over-conditioned (HBCS) group, receiving 6.8 or 7.2 MJ of NEL/kg of DM, respectively, during late lactation to reach the targeted differences in body condition score (BCS) and back fat thickness (BFT; NBCS: BCS <3.5, BFT <1.2 cm; HBCS: BCS >3.75, BFT >1.4 cm) until dry-off. During the dry period and next lactation, cows were fed the same diets, whereby differences in BCS and BFT were maintained: prepartum means were 3.16 ± 0.06 and 1.03 ± 0.07 cm (NBCS) vs. 3.77 ± 0.08 and 1.89 ± 0.11 cm (HBCS), postpartum means were 2.89 ± 0.06 and 0.81 ± 0.05 cm (NBCS) vs. 3.30 ± 0.06 and 1.38 ± 0.08 cm (HBCS). Blood and biopsies from liver, semitendinosus muscle, and subcutaneous adipose tissue (scAT) were sampled at d 49 antepartum, 3, 21, and 84 postpartum. Free BCAA were analyzed and the mRNA abundance of solute carrier family 1 member 5 (SLC1A5), SLC7A5, and SLC38A2 as well as branched-chain aminotransferase 2 (BCAT2), branched-chain α-keto acid dehydrogenase E1α (BCKDHA), and branched-chain α-keto acid dehydrogenase E1ß (BCKDHB) as well as the protein abundance of BCKDHA were assessed. Concentrations of all BCAA changed with time, most markedly in HBCS cows, with a nadir around calving. Apart from Ile, neither individual nor total BCAA differed between groups. The HBCS group had greater BCKDHA mRNA as well as higher prepartum BCKDHA protein abundance in scAT than NBCS cows, pointing to a greater oxidative capacity for the irreversible degradation of BCAA transamination products in scAT of over-conditioned cows. Prepartum hepatic BCKDHA protein abundance was lower in HBCS than in NBCS cows. In both groups, SLC1A5, SLC7A5, and BCAT2 mRNA were most abundant in scAT, whereas SLC38A2 was higher in scAT and muscle compared with liver, and BCKDHA and BCKDHB mRNA were greatest in liver and muscle, respectively. Our results indicate that scAT may be a major site of BCAA uptake and initial catabolism, with the former, however, being independent of BCS and time relative to calving in dairy cows.

Effects of overfeeding on the fatty acid profile and stearoyl-CoA desaturase-1 indices in the liver and subcutaneous adipose tissue in cats.

To evaluate the effect of overfeeding on fatty acid distribution and metabolism, especially stearoyl-CoA desaturase-1 (SCD-1) indices, 8 cats in the experimental and control groups (4 per group) were evaluated in this study. The experiments involved feeding the experimental group cats twice their daily energy requirement with a commercial diet for 4 weeks. The control group was fed the estimated daily energy requirement with the same diet. Body weight, feline body mass index, body condition score, several zoometry measurements, and plasma metabolites/hepatic injury markers were measured in all the cats before and after the experiment. In addition, the fatty acid profiles in the liver and subcutaneous adipose tissue were measured after the experiment. After 4 weeks of overfeeding, the experimental group demonstrated significant increases in hepatic C18:1, plasma triglyceride, and nonesterified fatty acid (NEFA) concentrations and in alanine aminotransferase activity. Furthermore, hepatic SCD-1 indices were positively correlated with body weight, feline body mass index, body condition score, and plasma NEFA concentration, although subcutaneous adipose tissue did not demonstrate any increase in SCD-1 indices in this study. The increase in hepatic SCD-1 indices might be enhanced by the inflow of plasma NEFA into the liver, and NEFA toxicity might stimulate C18:1 synthesis by SCD-1.

Subcutaneous adipose tissue imaging of human obesity reveals two types of adipocyte membranes: Insulin-responsive and -nonresponsive.

In adipose tissue, resistance to insulin's ability to increase glucose uptake can be induced by multiple factors, including obesity. Impaired insulin action may take place at different spatial loci at the cellular or subcellular level. To begin to understand the spatial response to insulin in human subcutaneous adipose tissue (hSAT), we developed a quantitative imaging method for activation of a major signaling node in the glucoregulatory insulin signaling pathway. After treatment with insulin or control media, biopsied tissues were immunostained for Akt phosphorylation at Thr-308/9 (pAkt) and then imaged by confocal fluorescence microscopy automated to collect a large grid of high resolution fields. In hSAT from 40 men and women with obesity, substantial heterogeneity of pAkt densities in adipocyte membranes were quantified in each image mosaic using a spatial unit of at least twice the size of the point spread function. Statistical analysis of the distribution of pAkt spatial units was best fit as the weighted sum of two separate distributions, corresponding to either a low or high pAkt density. A "high pAkt fraction" metric was calculated from the fraction of high pAkt distributed units over the total units. Importantly, upon insulin stimulation, tissues from the same biopsy showed either a minimal or a substantial change in the high pAkt fraction. Further supporting a two-state response to insulin stimulation, subjects with similar insulin sensitivity indices are also segregated into either of two clusters identified by the amount of membrane-localized pAkt.

Amino acid starvation-induced autophagy is involved in reduced subcutaneous fat deposition in weaning piglets derived from sows fed low-protein diet during gestation and lactation : Autophagy is involved in reduced fat deposition in maternal low-protein piglets.

PURPOSE: The study aimed to determine the effects of maternal low-protein (LP) diet on subcutaneous fat deposition of weaning piglets and the potential mechanism. METHODS: Sows were fed either a standard protein (SP, 15 and 18% crude protein) or a LP diet (50% protein levels of SP) throughout pregnancy and lactation. Subcutaneous fat and blood were sampled from male piglets at 28 days of age. Serum biochemical metabolites and hormone concentrations were detected with the enzymatic colorimetric methods. Serum-free amino acid (FAA) levels were measured by amino acid auto-analyzer. The mRNA and protein were measured by qRT-PCR and Western blot. RESULTS: Body weight, back fat thickness, triglycerides concentrations in subcutaneous fat tissue, and serum, as well as FFA concentrations were significantly reduced in LP piglets when compared with SP piglets. Further studies showed that mRNA and protein expression of acetyl-CoA carboxylase and fatty acid synthetase, two key enzymes of de novo lipogenesis, were significantly reduced in LP piglets, while mRNA expression and the lipolytic enzymes activities of lipolysis genes, adipose triglyceride lipase and hormone-sensitive lipase, were significantly increased. Furthermore, expression of autophagy-related gene 7 and autophagy maker gene microtubule-associated protein 1A/1B-light chain 3 (LC 3) as well as the conversion of LC3I to LC3II were significantly elevated, along with the expression of activating transcription factor-4 and eukaryotic translation initiation factor-2a. CONCLUSION: These results indicate that amino acid starvation-induced autophagy is involved in reduced subcutaneous fat deposition in maternal LP weaning piglets, demonstrating links between maternal protein restriction and offspring fat deposition.

Somatic PIK3CA mutations are present in multiple tissues of facial infiltrating lipomatosis.

BackgroundFacial infiltrating lipomatosis (FIL) is a congenital disorder that causes overgrowth of one side of the face. The purpose of this study was to determine whether PIK3CA mutations are present in tissues outside of the subcutaneous adipose.MethodsFIL tissues from three patients were dissected to enrich for cells from skin, subcutaneous tissue, orbicularis oris muscle, buccal fat, zygomatic bone, and mucosal neuroma. Endothelial cells within the affected tissue also were enriched using CD31 microbeads. Laser capture microdissection on formalin-fixed paraffin-embedded histologic sections was performed to collect specific cell types. DNA was extracted from each tissue and cell type, and measured for the abundance of mutant PIK3CA alleles using droplet digital PCR.ResultsWe detected mutant PIK3CA alleles in every tissue and cell type tested from each overgrown face; frequencies ranged from 1.5 to 53%. There were fewer mutant endothelial cells compared with nonendothelial cells, and the stromal cell compartment had the highest frequency of mutant cells in each tissue.ConclusionsPIK3CA mutations are not restricted to a single tissue or cell type in FIL. Overgrowth in this condition is likely due to the mutation arising in a cell that contributes to several different facial structures during embryogenesis.

The TMAO-Producing Enzyme Flavin-Containing Monooxygenase 3 Regulates Obesity and the Beiging of White Adipose Tissue.

Emerging evidence suggests that microbes resident in the human intestine represent a key environmental factor contributing to obesity-associated disorders. Here, we demonstrate that the gut microbiota-initiated trimethylamine N-oxide (TMAO)-generating pathway is linked to obesity and energy metabolism. In multiple clinical cohorts, systemic levels of TMAO were observed to strongly associate with type 2 diabetes. In addition, circulating TMAO levels were associated with obesity traits in the different inbred strains represented in the Hybrid Mouse Diversity Panel. Further, antisense oligonucleotide-mediated knockdown or genetic deletion of the TMAO-producing enzyme flavin-containing monooxygenase 3 (FMO3) conferred protection against obesity in mice. Complimentary mouse and human studies indicate a negative regulatory role for FMO3 in the beiging of white adipose tissue. Collectively, our studies reveal a link between the TMAO-producing enzyme FMO3 and obesity and the beiging of white adipose tissue.

Metalloproteinase 2 and 9 Activity Increase in Epicardial Adipose Tissue of Patients with Coronary Artery Disease.

BACKGROUND: Epicardial adipose tissue (EAT) is a visceral adipose tissue (AT) surrounding and infiltrating myocardium and coronary arteries. Increased EAT may represent a chronic inflammatory injury and a link with coronary artery disease (CAD). Metalloproteinases (MMPs) are involved in expansion of AT. OBJECTIVE: To evaluate MMP-2 and -9 behaviour in EAT from CAD patients. METHODS: In EAT and subcutaneous AT (SAT) from patients undergoing coronary artery bypass graft (CABG, n=26) or valve replacement (No CABG, n=18), MMP-2 and -9 activity and localization, inflammatory cells and vascular endothelial growth factor (VEGF) levels were determined. RESULTS: In EAT from CABG, MMP-2 and -9 activity was increased compared with No CABG (p=0.041 and p=0.027, respectively) and compared with SAT (p=0.005 and p=0.048, respectively). In CABG patients EAT showed higher infiltration of macrophages and T lymphocytes than SAT (p=0.01 and p=0.002, respectively). In No CABG patients no sign of cellular retention was observed in EAT or SAT. Vascular density was higher in EAT from CABG than No CABG (p=0.015) and it was directly correlated with MMP-2 (p=0.006) and MMP-9 (p=0.02). VEGF levels in EAT were directly associated with MMP-2 (p=0.016). CONCLUSION: In EAT from CABG patients the increase of MMP-2 and -9 activity and the presence of inflammatory cells would be partially responsible for extracellular matrix (ECM) remodeling and major vascular density necessary for EAT expansion. Improved knowledge of EAT behaviour may allow to identify new therapeutic targets for the treatment of CAD.

Sirt1 decreased adipose inflammation by interacting with Akt2 and inhibiting mTOR/S6K1 pathway in mice.

Sirtuin type 1 (Sirt1) and protein kinase B (Akt2) are associated with development of obesity and inflammation, but the molecular mechanisms of Sirt1 and Akt2 interaction on adipose inflammation remain unclear. To explore these mechanisms, a mouse model was used. Mice were fed with a high-fat diet (HFD) for 8 weeks, with interventions of resveratrol (RES) or nicotinamide (NAM) during the last 15 days. The HFD reduced Sirt1 mRNA in adipose tissue and elevated interleukin-6 (IL-6) expression. RES reduced the adipose tissue weight, increased the Sirt1 mRNA level, and reduced both mRNA and protein levels of IL-6, MCP-1, inducible nitric oxide synthase, and TNF-α by inhibiting phosphorylation of Akt2 in adipose tissue. Additionally, macrophage type I marker genes were reduced while macrophage type II marker genes were elevated by RES addition. Moreover, activation of Akt2 signal by using insulin significantly blunted the inhibitory effect of RES on adipose inflammation. Immunoprecipitation assay demonstrated that RES enhances the protein-protein interaction between Sirt1 and Akt2, but NAM inhibits this interaction. Furthermore, Sirt1 significantly reduced the levels of raptor and inactivated mammalian target of rapamycin (mTOR)C1 signal by interacting with Akt2, and confirmed that RES attenuated adipose inflammation by inhibiting the mTOR/S6K1 pathway via rapamycin.

Macrophage Infiltration into Subcutaneous Adipose Tissue is Associated with Local Levels of 11BHSD1.

The present study aimed to evaluate the infiltration of macrophages in form of crown-line structures (CLS) in subcutaneous adipose tissue (SAT) of obese individuals, and to investigate the effect of these on both metabolic parameters and adipose tissue 11-beta-hydroxysteroid dehydrogenase type 1 (11BHSD1) enzyme levels. A total of 53 obese (10 men, 43 woman) enrolled in the study. Body mass index (BMI), waist circumference (WC), hip circumfrence, and systolic (SBP) and diastolic blood pressures (DBP) of all subjects were recorded. Insulin resistance was determined using the homeostasis model assessment (HOMA). The concentration of SAT, tumor necrosis factor (TNF)-α, interleukin (IL)-6, 11BHSD1 were performed by enzyme-linked immunosorbent assay (ELISA) method. The infiltration of macrophages in form of CLS in adipose tissue were determined using cell-specific stains against CD68. There was no significant difference between the CLS+group and the CLS- group in terms of age, gender, BMI, WC, waist-to-hip circumference ratio (WHR), SBP and DBP levels. Fasting plasma glucose (FPG), HOMA-IR, insulin and SAT TNF-α levels were higher in the CLS+group compared to the CLS- group. FPG and SAT TNF-α levels were significantly higher in participants with high CLS density compared to participants with low density CLS. SAT 11BHSD1 levels was significant higher in the CLS+group compare to the CLS- group and in the high CLS density group compared to the low density group. In conclusion, the infiltration of macrophages in the form of CLS in SAT is associated with increased 11BHSD1 levels. It may be an important mechanism in the development of metabolic disorders.

Peroxisome proliferator-activated receptor γ activation favours selective subcutaneous lipid deposition by coordinately regulating lipoprotein lipase modulators, fatty acid transporters and lipogenic enzymes.

AIM: Peroxisome proliferator-activated receptor (PPAR) γ activation is associated with preferential lipoprotein lipase (LPL)-mediated fatty acid storage in peripheral subcutaneous fat depots. How PPARγ agonism acts upon the multi-level modulation of depot-specific lipid storage remains incompletely understood. METHODS: We evaluated herein triglyceride-derived lipid incorporation into adipose tissue depots, LPL mass and activity, mRNA levels and content of proteins involved in the modulation of LPL activity and fatty acid transport, and the expression/activity of enzymes defining adipose tissue lipogenic potential in rats treated with the PPARγ ligand rosiglitazone (30 mg kg(-1)  day(-1) , 23 days) after either a 10-h fasting period or a 17-h fast followed by 6 h of ad libitum refeeding. RESULTS: Rosiglitazone stimulated lipid accretion in subcutaneous fat (SF) ~twofold and significantly reduced that of visceral fat (VF) to nearly half. PPARγ activation selectively increased LPL mass, activity and the expression of its chaperone LMF1 in SF. In VF, rosiglitazone had no effect on LPL activity and downregulated the mRNA levels of the transendothelial transporter GPIHBP1. Overexpression of lipid uptake and fatty acid transport proteins (FAT/CD36, FATP1 and FABP4) and stimulation of lipogenic enzyme activities (GPAT, AGPAT and DGAT) upon rosiglitazone treatment were of higher magnitude in SF. CONCLUSIONS: Together these findings demonstrate that the depot-specific transcriptional control of LPL induced by PPARγ activation extends to its key interacting proteins and post-translational modulators to favour subcutaneous lipid storage.

Safety, pharmacokinetics and pharmacodynamics of BI 135585, a selective 11ß-hydroxysteroid dehydrogenase-1 (HSD1) inhibitor in humans: liver and adipose tissue 11ß-HSD1 inhibition after acute and multiple administrations over 2 weeks.

AIMS: To assess the safety and pharmacokinetic and pharmacodynamic characteristics of BI 135585, a selective 11ß-hydroxysteroid dehydrogenase-1 (11ß-HSD1) inhibitor, after single- and repeated-dose administration. METHODS: The single-dose study included open-label administration of 200 mg BI 135585 in healthy volunteers, while in the multiple-dose study, we carried out randomized, double-blind administration of 5-200 mg BI 135585 or placebo once daily over 14 days in patients with type 2 diabetes (T2DM). Assessments included 11ß-HSD1 inhibition in the liver (urinary tetrahydrocortisol (THF)/tetrahydrocotisone (THE) ratio) and in subcutaneous adipose tissue (AT) ex vivo and determination of hypothalamus-pituitary-adrenal (HPA) axis hormone levels. RESULTS: No major safety issues occurred with BI 135585 administration. The HPA axis was mildly activated with slightly increased, but still normal adrenocorticotropic hormone levels, increased total urinary corticoid excretion but unchanged plasma cortisol levels. After multiple doses of 5-200 mg BI 135585, exposure (area under the curve) increased dose-proportionally and half-life was 55-65 h. The urinary THF/THE ratio decreased, indicating liver 11ß-HSD1 inhibition. Median 11ß-HSD1 enzyme inhibition in the AT reached 90% after a single dose of BI 135585, but was low (31% or lower) after 14 days of continuous treatment. CONCLUSIONS: BI 135585 was safe and well tolerated over 14 days and can be dosed once daily. Future studies are required to clarify the therapeutic potential of BI 135585 in view of its effects on 11ß-HSD1 inhibition in AT after single and multiple doses. Enzyme inhibition in the AT was not adequately predicted by the urinary THF/THE ratio.

Steroid sulfatase activity in subcutaneous and visceral adipose tissue: a comparison between pre- and postmenopausal women.

OBJECTIVE: Adipose tissue is an important extragonadal site for steroid hormone biosynthesis. After menopause, estrogens are synthesized exclusively in peripheral tissues from circulating steroid precursors, of which the most abundant is dehydroepiandrosterone sulfate (DHEAS). Our aim was to study activity of steroid sulfatase, an enzyme hydrolyzing DHEAS, and expression of steroid-converting enzyme genes in subcutaneous and visceral adipose tissue derived from pre- and postmenopausal women. DESIGN: Serum and paired abdominal subcutaneous and visceral adipose tissue samples were obtained from 18 premenopausal and seven postmenopausal women undergoing elective surgery for non-malignant reasons in Helsinki University Central Hospital. METHODS: To assess steroid sulfatase activity, radiolabeled DHEAS was incubated in the presence of adipose tissue homogenate and the liberated dehydroepiandrosterone (DHEA) was measured. Gene mRNA expressions were analyzed by quantitative RT-PCR. Serum DHEAS, DHEA, and estrogen concentrations were determined by liquid chromatography-tandem mass spectrometry. RESULTS: Steroid sulfatase activity was higher in postmenopausal compared to premenopausal women in subcutaneous (median 379 vs 257 pmol/kg tissue per hour; P=0.006) and visceral (545 vs 360 pmol/kg per hour; P=0.004) adipose tissue. Visceral fat showed higher sulfatase activity than subcutaneous fat in premenopausal (P=0.035) and all (P=0.010) women. The mRNA expression levels of two estradiol-producing enzymes, aromatase and 17ß-hydroxysteroid dehydrogenase type 12, were higher in postmenopausal than in premenopausal subcutaneous adipose tissue. CONCLUSIONS: Steroid sulfatase activity in adipose tissue was higher in postmenopausal than in premenopausal women suggesting that DHEAS, derived from the circulation, could be more efficiently utilized in postmenopausal adipose tissue for the formation of biologically active sex hormones.

[Effect of free fatty acids on CYP19A1 (aromatase) gene expression in human adipose tissue stromal vascular fraction cells].

Aromatase plays an important role in the estrogen biosynthesis. Its gen (CYP19A1) is expressed in preadipocytes (stromal vascular fraction, SVF) of adipose tissue. Estrogens are found to be protective for metabolism homeostasis, and cardiovascular system. Disturbed dietary and endogenous fatty acids (FAs) turnover is responsible for development of metabolic syndrome and it complications. Aim of the work was to investigate the effect of physiological concentrations of acids: arachidonic (AA), oleic (OA), palmitynoic (PA) and eikozapentaenoic (EPA) on CYP19A1 expression in differentiating human SVF, able to form adipocytes as well as endothelial cells. Material and Methods: Human (n=38 healthy woman) SVF cells were isolated from subcutaneous adipose tissue harvested intrasurgery. SVF cells were incubated in proadipogenic or angiogenic media to obtain adipocytes (Adipo-SVF) or endothelial (Angio-SVF) cells (confirmed by microarray). Changes in the CYP19A1 expression induced by 24hs incubation in the presence of FAs (10 ­ 30 µM )were monitored by the Real time PCR (qRT -PCR). Results: The aromatase gene expression correlated positively with BMI of patients, but only in group of obese or overweight women. The negative correlation was found in the group of young, slim women. The highest expression of aromatase was found in the fresh, not differentiated SVF. In differentiating to endothelial cells (Angio - SVF) OA inhibited (p=0.008), when n-3 polyunsaturated AA activated (p=0.003) the CYP19A1 gene expression. In differentiating to preadipocytes (Adipo-SVF) AA significantly (p=0.031) inhibited CYP19A1 expression. Conclusion: The changes in the aromatase gene expression in differentiating SVF has been confirmed. The different effect of the dietary FA (OA vs. AA) on the aromatase gene expression argue for the role of the locally formed proangiogenic estrogens.

Subcutaneous Adipose Tissue Type II Deiodinase Gene Expression Reduced in Obese Individuals with Metabolic Syndrome.

The present study aimed to evaluate the role of subcutaneous adipose tissue (SAT) type II deiodinase enzyme gene (DIO2) expression in developing metabolic syndrome (MetS). A total of 51 obese patients with MetS and without MetS and 13 healthy subjects enrolled in the study. Body mass index (BMI), waist circumference (WC), waist-to-hip circumference ratio (WHR), hip circumference, and systolic (SBP) and diastolic blood pressures (DBP) of all subjects were recorded. Fasting plasma glucose (FPG), fasting plasma insulin, high density lipoprotein- cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), total cholesterol (TC) and triglyceride (TG) of all subjects were analyzed. Expression of the DIO2 gene in adipose tissue was determined by reverse transcription polymerase chain reaction (qRT-PCR). BMI, WC and WHR were not significantly difference between obese with and without MetS. SBP, DBP, FPG and TG were significantly higher in obese with MetS group than obese without MetS group. While the free triiodothyronine (T3) level was in the normal range in all group, it was significantly lower in the obese with MetS than both obese without MetS and control group. DIO2 expression was significantly lower in the obese with MetS group compared to the control. In correlation analysis, DIO2 expression was negatively correlated with DBP, TG and homeostasis model assessment of insulin resistance (HOMA-IR) levels and positively correlated with free T3. In conclusion, the reduction of SAT DIO2 expression is negatively correlated with DBP and TG levels that are associated with the MetS. This might have an effect on developing MetS. We believe that DIO2 gene may be an important molecular target for future studies in developing targeted treatment options for obese people with MetS.

Vitamin D Regulates Fatty Acid Composition in Subcutaneous Adipose Tissue Through Elovl3.

Fatty acids (FAs) are a major energy source in the body. White adipose tissue (WAT) is a primary site where FAs are stored as triacylglycerols. Brown adipose tissue also stores and recruits FAs as a carbon source for uncoupled ß-oxidation during thermogenesis. The deletion of the vitamin D nuclear hormone receptor (VDR) gene in mice (VDRKO) results in a lean WAT phenotype with increased levels of expression of the brown adipose tissue marker Ucp1 in the WAT. However, the impact of vitamin D/VDR on FA composition in WAT has not been explored in detail. To address this question, we examined the FA composition of sc and visceral white adipose depots of VDRKO mice. We found that the levels of a subset of saturated and monounsaturated FAs of C18-C24 are specifically increased in the sc adipose depot in VDRKO mice. We revealed that a specific elongase enzyme (Elovl3), which has an important role in brown fat biology, is directly regulated by VDR and likely contributes to the altered FA composition in VDRKO mice. We also demonstrate that Elovl3 is regulated by vitamin D in vivo and tissue specifically in the sc WAT depot. We discovered that regulation of Elovl3 expression is mediated by ligand-dependent VDR occupancy of a negative-response element in the promoter proximal region of the Elovl3 gene. These data suggest that vitamin D/VDR tissue specifically modulates FA composition in sc WAT through direct regulation of Elovl3 expression.

Downregulation of de Novo Fatty Acid Synthesis in Subcutaneous Adipose Tissue of Moderately Obese Women.

The purpose of this work was to evaluate the expression of fatty acid metabolism-related genes in human adipose tissue from moderately obese women. We used qRT-PCR and Western Blot to analyze visceral (VAT) and subcutaneous (SAT) adipose tissue mRNA expression involved in de novo fatty acid synthesis (ACC1, FAS), fatty acid oxidation (PPARα, PPARδ) and inflammation (IL6, TNFα), in normal weight control women (BMI < 25 kg/m², n = 35) and moderately obese women (BMI 30-38 kg/m², n = 55). In SAT, ACC1, FAS and PPARα mRNA expression were significantly decreased in moderately obese women compared to controls. The downregulation reported in SAT was more pronounced when BMI increased. In VAT, lipogenic-related genes and PPARα were similar in both groups. Only PPARδ gene expression was significantly increased in moderately obese women. As far as inflammation is concerned, TNFα and IL6 were significantly increased in moderate obesity in both tissues. Our results indicate that there is a progressive downregulation in lipogenesis in SAT as BMI increases, which suggests that SAT decreases the synthesis of fatty acid de novo during the development of obesity, whereas in VAT lipogenesis remains active regardless of the degree of obesity.

Increased PUFA Content and 5-Lipoxygenase Pathway Expression Are Associated with Subcutaneous Adipose Tissue Inflammation in Obese Women with Type 2 Diabetes.

Obese women with type 2 diabetes mellitus (T2DM) have more inflammation in their subcutaneous white adipose tissue (sWAT) than age-and-BMI similar obese women with normal glucose tolerance (NGT). We aimed to investigate whether WAT fatty acids and/or oxylipins are associated with the enhanced inflammatory state in WAT of the T2DM women. Fatty acid profiles were measured in both subcutaneous and visceral adipose tissue (vWAT) of 19 obese women with NGT and 16 age-and-BMI similar women with T2DM. Oxylipin levels were measured in sWAT of all women. Arachidonic acid (AA) and docosahexaenoic acid (DHA) percentages were higher in sWAT, but not vWAT of the T2DM women, and AA correlated positively to the gene expression of macrophage marker CD68. We found tendencies for higher oxylipin concentrations of the 5-LOX leukotrienes in sWAT of T2DM women. Gene expression of the 5-LOX leukotriene biosynthesis pathway was significantly higher in sWAT of T2DM women. In conclusion, AA and DHA content were higher in sWAT of T2DM women and AA correlated to the increased inflammatory state in sWAT. Increased AA content was accompanied by an upregulation of the 5-LOX pathway and seems to have led to an increase in the conversion of AA into proinflammatory leukotrienes in sWAT.

Omental adipocyte hypertrophy relates to coenzyme Q10 redox state and lipid peroxidation in obese women.

Occurrence of oxidative stress in white adipose tissues contributes to its dysfunction and the development of obesity-related metabolic complications. Coenzyme Q10 (CoQ10) is the single lipophilic antioxidant synthesized in humans and is essential for electron transport during mitochondrial respiration. To understand the role of CoQ10 in adipose tissue physiology and dysfunction, the abundance of the oxidized and reduced (CoQ10red) isoforms of the CoQ10 were quantified in subcutaneous and omental adipose tissues of women covering the full range of BMI (from 21.5 to 53.2 kg/m(2)). Lean women displayed regional variations of CoQ10 redox state between the omental and subcutaneous depot, despite similar total content. Obese women had reduced CoQ10red concentrations in the omental depot, leading to increased CoQ10 redox state and higher levels of lipid hydroperoxide. Women with low omental CoQ10 content had greater visceral and subcutaneous adiposity, increased omental adipocyte diameter, and higher circulating interleukin-6 and C-reactive protein levels and were more insulin resistant. The associations between abdominal obesity-related cardiometabolic risk factors and CoQ10 content in the omental depot were abolished after adjustment for omental adipocyte diameter. This study shows that hypertrophic remodeling of visceral fat closely relates to depletion of CoQ10, lipid peroxidation, and inflammation.